Calpain and DNA encoding the same

ABSTRACT

A calpain protein which is specific for the retina in eye tissues containing a protein having an amino acid sequence represented by SEQ ID NO: 1 in Sequence Listing; a DNA represented by SEQ ID NO: 2 in Sequence Listing which encodes the above protein; a vector containing this DNA; a transformant transformed by this vector; and a process for producing the calpain protein which comprises culturing the transformant.

This is a 371 application of PCT/JP99/00903 filed Feb. 26, 1999.

FIELD OF THE INVENTION

The present invention relates to newly identified calpain, Rt88 protein, which has been of the retina in eye tissues, and a DNA encoding it.

BACKGROUND OF THE INVENTION

Calpain is present, in particular, in the cytoplasm of animal cells and is a cysteine protease which is activated by calcium. Several molecular species have been known in calpain. For analyzing the structure, their cDNA's have been cloned and, at present, the presence of μ-and m-calpain which are generally expressed in various tissues, as well as tissue-specific calpain such as, for example, p94 which is specifically expressed in a skeleton muscle is revealed [Seikagaku (Biochemistry), Vol. 65, No. 7, pp. 537-552 (1993); Jikken Igaku (Experimental Medicine), Vol. 13, No. 9, pp. 35-42 (1995)].

Although details of physiological functions of calpain are not yet elucidated, calpain has been considered to have functions of a calcium receptor in cells and to be concerned in, for example, signal transduction, control of transcription, propagation and differentiation of cells, and the like.

Recently, it has been reported that a mutant gene of calpain p94 specifically expressed in a skeleton muscle is one of causative genes of a kind of dystrophy, myodystropy, which is known to be a disease wherein differentiated cells fall into spontaneous degeneration or atrophy without any anticipation disorder such as inflammation or injury (Isabelle Richard et al., Cell, 81, 28-40 (1995)). In addition, it has been found that p94 protein is decreased in myodystrophy (Melissa J. Spencer et al., Journal of the Neurological Science, 146, 173-178 (1997)).

On the other hand, in general, retinal degenerative diseases are divided into dystrophy and other degenerative diseases. Dystrophy is hereditary and, in many cases, the prognosis of vision is pessimistic. Then, dystrophy is of importance from clinical viewpoint (Yoshihiro Hotta, “The Cause of Retinal Degeneration” in Atarashii Ganka (Journal of the Eye), 13 (7): 993-1001, 1996). In particular, at present, pigmentary retinal degeneration is designated as an objective disease in the Ministry of Health and Welfare Research Work for Treatment of Specific Diseases.

However, no study of the relation between dystrophy and calpain in retinal degenerative diseases has been found heretofore in the prior art.

OBJECTS OF THE INVENTION

The main object of the present invention is to investigate calpain which is tissue-specifically expressed in the retina of eye tissues, to isolate its gene, to determine the structure of a protein and to use them in studies of diseases in ophthalmologic field and in treatment and prevention of diseases in ophthalmologic field, in particular, retinal degenerative diseases.

This object as well as other objects and advantages of the present invention will become apparent to those skilled in the art with reference to the attached drawings.

BRIEF EXPLANATION OF DRAWINGS

FIG. 1 illustrates a combination of four primers and size of the products amplified by RT-PCR in Example 1 hereinafter.

FIGS. 2A and 2B are photographs showing electrophoretic migration patterns of the PCR products No. 1 and No. 2 in FIG. 1, respectively.

FIGS. 3A and 3B are photographs showing electrophoretic migration patterns of the PCR products No. 3 and No. 4 in FIG. 1, respectively.

FIGS. 4A and 4B are photographs showing an electrophoretic migration pattern of the PCR product No. 4 in FIG. 1 after digestion with restriction enzymes KpnI and EcoRI.

FIG. 5 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94.

FIG. 6 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94 (continued FIG. 5).

FIG. 7 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94 (continued FIG. 6).

FIG. 8 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94 (continued FIG. 7).

FIG. 9 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94 (continued FIG. 8).

FIG. 10 illustrates a comparison of the cDNA sequence obtained in Example 1 hereinafter with that of p94 (continued FIG. 9).

FIG. 11 illustrates a comparison of an amino acid sequence deduced from the cDNA of SEQ ID NO: 2 with the amino acid sequence of p94.

FIG. 12 illustrates a comparison of an amino acid sequence deduced from the CDNA of SEQ ID NO: 2 with the amino acid sequence of p94 (continued FIG. 11).

FIG. 13 is a photograph showing results of northern blotting of the Rt88 mRNA obtained in Example 3, hereinafter.

FIG. 14 illustrates electrophoretic migration patterns of a protein reacted with the Rt88 antibody obtained in Example 5 hereinafter.

FIG. 15 illustrates electrophoretic migration patterns of Rt88 reacted with the Rt88 antibody obtained in Example 5 hereinafter and PentaHis antibody.

FIG. 16 is a photograph showing electrophoretic migration patterns of the PCR products in Example 7 hereinafter.

SUMMARY OF THE INVENTION

Since calpain is concerned with myodystrophy, the present inventors have expected that, it calpain which is tissue-specifically expressed in eye tissues can be found out, new routes for studying dystrophy in retinal degenerative diseases can be provided, and causes of, for example, retinopathy can be elucidated by examining an expression amount and gene mutation of this calpain in retinopathy, and that further improvement of the examination can establish therapy of such a disease. In view of the above, the present inventors have studied intensively.

That is, for the purpose of finding out novel calpain, the present inventors have designed primers based on a DNA of skeleton muscle-specific calpain, p94, and have succeeded in obtaining a DNA (CDNA) encoding new calpain from a total RNA of a rat retinal tissue by using RT-PCR technique and 5′ RACE. Based on the sequence of this cDNA, an amino acid sequence of this calpain has been deduced.

Expression of the cDNA by a host can be expected to produce a protein corresponding to the calpain. In addition, the calpain can be expected to be used as an reagent in studies in connection with, for example, differentiation, growth, propagation, life conservation, and signal transduction of animal cells. Further, it can be expected to be used as medicine for elucidating and treating diseases.

The present invention has been completed based on these findings and provides a protein having an amino acid sequence represented by SEQ ID NO: 1 in the Sequence Listing, in particular, a protein corresponding to calpain derived from the retina.

The present invention also provides a DNA encoding the protein, a vector comprising the DNA and a transformant transformed with the vector. The DNA includes a nucleotide sequence represented by SEQ ID NO: 2 in the Sequence Listing and those hybridizable with it under stringent conditions.

Further, the present invention provides a process for producing the protein which comprises culturing the transformant in a culture medium to produce and accumulate the protein having the amino acid sequence represented by SEQ ID NO: 1 in the culture.

Furthermore, the present invention provides a inhibitor to the protein of the present invention; a pharmaceutical composition for treating or preventing retinal disorders which comprises an anti-sense DNA, anti-sense RNA or sense DNA of a MRNA for translating the protein or a triplet DNA of a genomic DNA expressing a mRNA for translating the protein; and a composition for retina diagnosis which comprises a genomic DNA expressing a mRNA for translating the protein.

DETAILED DESCRIPTION OF THE INVENTION

The protein of the present invention includes a protein having a molecular weight of about 88 kDa and having an amino acid sequence represented by SEQ ID NO: 1 of the Sequence Listing, and a protein containing the protein in its molecule. In particular, the protein having the protease activity of calpain. Although there are many isozymes in calpain, they have the same basic skeleton which is divided into four functional domains (see FIG. 11 and FIG. 12). The protease activity of calpain is derived from Domain II which is a protease region having homology to a cysteine protease.

The protease activity of calpain can be represented by its capability of decomposing a substrate protein. Examples of the substrate include cytoskeletal protein (e.g., spectrin, MAP-2, tau factor, neurofilaments H, M and L, α-actinin), membrane-binding receptor protein (e.g., EGF receptor, AMPA receptor, calcium pump, anion channel, calcium release channel, L-type calcium channel, G-protein), calmodulin-binding protein (e.g., calcium pump, calcineurin, CaM-dependent protein kinase II, myosin L-chain kinase, neuromodulin, connexin, IP3 kinase), enzyme (e.g., protein kinase C, HMG-CoA reductase, cAMP-dependent kinase, pyruvate kinase, phosphorylase kinase), myofibril protein (e.g., troponin I, troponin T, tropomyosin, myosin), transcription factor (e.g., c-fos, c-jun, Pit-1, Oct-1, CP1a and b, c-Myc) and the like (Kevin K. Wand and Po-wai Yuen, Adv. Pharmacol., 37, 117-152 (1997)). The capability of decomposing a substrate protein can be determined by a known method. For example, by using FITC casein as a substrate, the intensity of fluorescence of a FITC casein fragment in an acid soluble fraction decomposed from the substrate can be determined (David, L. L. and Shearer, T. R., Exp. Eye Res., 42, 227-238 (1986)). One unit of calpain used herein is defined as an amount of an enzyme which releases one pg of a FITC casein fragment per one minute.

The calpain of the present invention is considered to be one of calpain families specifically expressed only in the retina in view of the expression state of its mRNA in each tissue.

The DNA of the present invention can be obtained by, first, extracting a total RNA from a rat tissue with a commercially available kit for extracting a total RNA according to a protocol attached thereto.

Then, regarding the total RNA obtained, 3′ terminus-cloning is carried out by RT-PCR with gene specific primers (GSP's) designed based on a cDNA sequence of known skeletal muscle-specific calpain, p94. For example, the total RNA is subjected to a reverse transcription reaction with oligo dT primer and the resultant cDNA is amplified with sense and anti-sense GSP's having the sequence represented by SEQ ID NOS: 3 to 6. This PCR product is sub-cloned with, for example, a commercially available cloning kit to conduct 3′ terminus-cloning, thereby determining the 3′ terminus nucleotide sequence.

On the other hand, since the 5′ terminus of a retina-derived CDNA cannot be amplified by PCR, a nucleotide sequence is determined by 5′ RACE. For example, the above-extracted total RNA is subjected to a reverse transcription reaction similar to that in the sequence determination of the 3′ terminus by using a commercially available 5′ RACE system to prepare a cDNA for a first strand. However, as the anti-sense primer, the GSP having the sequence of SEQ ID NO: 6 is used. After purification of the cDNA thus prepared, TdT is added thereto and the resultant cDNA is amplified by PCR. As the sense primer, that of the protocol of the kit is used, and the GSP having the sequence of SEQ ID NO: 7 is used as the anti-sense primer. According to the same manner as that described above, the PCR product is subjected to sub-cloning to determine the 5′ terminus nucleotide sequence.

The fact that the 5′ terminus of a retina-derived cDNA cannot be amplified by primers based on the cDNA sequence of the skeleton muscle-specific calpain, p94 shows that the sequence of the 5′ terminus is different from that of p94.

The whole nucleotide sequence is determined based on respective nucleotide sequences of 3′ and 5′ termini thus determined. Thus, the nucleotide sequence represented by SEQ ID NO: 2 has been determined. Differences between the sequence represented by SEQ ID NO: 2 and the skeleton muscle-specific calpain, p94, are recognized at exon 1 and exons 15 and 16.

SEQ ID NO: 1 represents a novel amino acid sequence deduced from the open reading frame of the nucleotide sequence of cDNA thus determined. The nucleotide sequence from 67th base to 2337th base encodes the protein of SEQ ID NO: 1.

The DNA of the present invention includes that hybridizable with the above sequence under stringent conditions. The stringent conditions mean that sequences hybridize to each other only when they have 95% or more homology. For example, the stringent conditions include such conditions as incubation in a solution containing 50% formaldehyde, 5×SSC (150 mM NaCl, 15 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5×Denhartdt's solution, 10% dextran sulfate and 20 μg/ml denatured salmon sperm DNA at 42° C. overnight, and then washing with 0.1×SSC at about 65° C.

The DNA of the present invention can integrate into a vector according to a conventional method, for example, by ligation with T4DNA ligase which is an enzyme to join 5′—P end and 3′—OH end of DNAs to ligate a DNA to be inserted to the vector. As a vector for expressing a protein, for example, pQE (QIAGEN), pET (NOVAGEN), pTrcHis (Invitorogen) and the like can be used.

Further, the present invention provides a transformant prepared by transforming host cells with an expression vector into which the DNA of the present invention has been integrated. Transformation can be carried out according to a conventional method such as that using competent cells obtained by treatment with calcium chloride, electroporation, and the like. For example, E. coli cells, cultured cells and the like which are capable of incorporating a foreign DNA can be used as the competent cells. As the host cells, both eukaryotic cells and prokaryotic cells can be used. For example, animal cells (COS cell, fibroblast or epithelial cell, lymphocyte, hematopoietic cell, ES cell, etc.), baculovirus, yeast, E. coli, Xenopus laevis oocyte, wheat germ, reticulocyte and the like can be used.

The protein of the present invention can be obtained by culturing the transformant thus obtained according to a conventional method. The protein of the present invention is produced in the cytoplasm.

For separation and purification of the protein of the present invention, for example, microbial cells or cells are collected after culturing them by a known method, and they are disrupted in a suitable buffer solution by sonication or the like, followed by centrifugation or the like to obtain the protein as a crude extract. The buffer solution may contain a protein denaturant such as urea, guanidine hydrochloride, etc., and a surfactant such as Triton, etc. When the protein or the like is secreted in a culture medium, microbial cells or cells are separated after culturing them according to a per se known method to collect the supernatant. Purification of the protein of the present invention thus obtained can be carried out by appropriately combining known methods, for example, salting out, gel filtration, SDS-polyacrylamide gel electrophoresis, affinity chromatography and the like. When the protein is obtained in its free form, it can be converted into a suitable salt by a per se known method [for example, salts with alkali metals (e.g., sodium, potassium, etc.), addition salts with inorganic acids (e.g., hydrochloric acid, phosphoric acid, hydrobromic acid, sulfuric acid, etc.), addition salts with organic acids (e.g., acetic acid, formic acid, propionic acid, fumaric acid, maleic acid, succinic acid, tartaric acid, citric acid, benzoic acid, methanesulfonic acid, benzenesulfonic acid, etc.)]. On the other hand, when the protein is obtained as a salt, it can be converted into its free form by a per se known method.

In the protein of the present invention, its C-terminus may be in the form of an amide (—CONH₂) or an ester (—COOR), wherein R of the ester is, for example, a lower alkyl group such as methyl, ethyl, propyl, butyl, etc., an aryl group such as phenyl, naphthyl, etc., an aralkyl group such as benzyl, phenethyl, etc., pivaloyloxymethyl group or the like. In addition, the protein of the present invention includes that wherein its carboxyl (—COOH) or carboxylate (—COO⁻) group other than such a group at the C-terminus is amidated or esterified as above. Further, the protein of the present invention includes a protected protein wherein a substituent on a side chain of the amino acid in the molecule (e.g., hydroxyl group, thiol group, amino group, guanidino group, etc.) is protected with a suitable protecting group (e.g., formyl group, an acyl group, etc.), or a protein to which a saccharide chain is attached.

The presence or activity of the protein or its salt of the present invention thus obtained can be confirmed by immunoblotting technique using a specific antibody, the protease activity of the above calpain, and the like.

An antibody against the protein or its salt of the present invention may be any polyclonal or monoclonal antibody as far as it can recognize the protein of the present invention. The antibody against the protein of the present invention can be produced according to a per se known process for producing an antibody or antiserum. For example, an immunogen itself such as the protein of the present invention, the peptide of SEQ ID NO: 11 or the like, or a complex thereof with a carrier protein is prepared and a mammal is immunized with it. A material containing an antibody against the protein of the present invention or the like is collected from the immunized animal and the antibody is separated and purified. Examples of the mammal include rabbit, guniea pig, mouse, rat and the like. When the antigen is administered, a complete adjuvant or an incomplete adjuvant may also be administered to enhance the antibody productivity. Normally, it is administered once every 2 to 6 weeks, about 2 to 10 times in all. The antibody can be collected from blood of the immunized animal. An antibody titer can be measured by dot blotting technique, ELISA, etc. Separation and purification of the antibody can be carried out according to that of an immunoglobulin.

The protein obtained is retina specific calpain and there is a high possibility that this is concerned in various retinal diseases, because a possible pathogenesis of retinal diseases is considered to be a mutant gene of calpain, and manifestation of various diseases is considered to be excess expression of a gene of this retina specific calpain and its protein or failure of expression thereof due to physical disorders.

Therefore, the protein of the present invention can be used as an agent useful for diagnosis, or prevention and treatment of various retinal diseases. In addition, it can be used for screening such an agent, and the like. Further, it can be used for researches of these diseases, and the like.

For example, it is considered that retinal diseases are manifested by an abnormal rise in the protein of the present invention due to ischemia, retinal neovascularization, or the like. Then, an inhibitor of the protein which can be selected by measuring a protease activity using FITC casein as a substrate is useful as an agent for preventing and treating these diseases.

In addition, it is also considered that retinal diseases are manifested by a rise in expression of a mRNA for translation of the protein of the present invention due to ischemia, retinal neovascularization, or the like. Then, these diseases can be treated by injecting retroviruses or cationic liposomes, into which an antisense DNA, a triplet DNA or an antisense RNA has been integrated, in the vitreous or subretinal cavity. Further, they can be treated by transplanting gene transferred cells. The antisense DNA can be obtained as a DNA hybridizable to a mRNA of the protein of the present invention. The triplet DNA can be obtained as a DNA hybridizable to a genomic DNA which expresses a mRNA of the protein of the present invention. The antisense RNA can be obtained as a RNA hybridizable to a mRNA of the protein of the present invention.

Further, since there is a report about hereditary pigmentary retinal degeneration due to pint mutation of rhodopsin gene [K. Kajiwara, Atarashii Ganka (Journal of the Eye), 12(2): 239-250, 1995], it is considered that a mutant gene of retina derived calpain also causes retinal diseases. These diseases can be treated by injecting a vector, into which a sense DNA to a mRNA for translation of the protein of the present invention has been integrated, in the vitreous or subretinal cavity, or by transplanting gene transferred cells to express the protein.

Furthermore, retinal diseases can be diagnosed by collecting a genomic DNA from a retina or blood sample of a patient to confirm a mutant gene by SSCP (single-stranded conformation polymorphism), DGGE (denaturing gradient gel electrophoresis), differential display, or the like.

The following Examples further illustrate the present invention in detail but are not to be construed to limit the scope of the present invention.

EXAMPLE 1 (1) Extraction of Total RNA From Each Tissue

Each tissue (lens, retina, brain, and muscle), of a 14-day old Sprague-Dawley male rat was removed and the total RNA was extracted therefrom according to the protocol of a total RNA extraction kit, TRIzol™ agent (Life Technologies).

First, TRIzol™ agent was added to the tissue (1 ml/100 mg tissue). The mixture was homogenized and the homogenate was incubated at room temperature for 5 minutes. Chloroform (0.2 ml/ml TRIzol™ agent) was added thereto and the mixture was shaken lightly for 15 seconds. After shaking, the mixture was incubated at room temperature for 5 minutes and centrifuged at 12,000×g at 4° C. for 15 minutes. After centrifugation, the supernatant was transferred to a new tube and isopropanol (0.5 ml) was added thereto. The mixture was shaken lightly and further centrifuged at 12,000×g at 4° C. for 15 minutes. When a pellet was confirmed, it was washed once or twice with 75% ethanol. Then, the pellet was dissolved in RNase and DNase-free water and the concentration was measured by the absorbance A260/280.

(2) 3′ Terminus-cloning

GSP's for PCR were designed based on the cDNA sequence (3138 bases) of skeleton muscle-specific calpain p94, and four (4) PCR products were obtained by changing combination of GSP's.

SEQ ID NOS: 3, 4, 5 and 6 of the Sequence Listing represent the sense and antisense sequences used. specifically, a reverse transcription reaction about the total retinal RNA extracted in the above (1) was carried out at 42° C. for 50 minutes and then 70° C. for 15 minutes by using oligo dT primer. Then, the resultant cDNA was amplified by repeating a PCR cycle of 94° C. for 1 minute, 53° C. for 1 minute and then 72° C. for 3 minutes, 30 times using the combination of GSP's of SEQ ID NOS: 3 and 4 in the Sequence Listing; a PCR cycle of 94° C. for 45 seconds, 53° C. for 45 seconds and then 72° C. for 1 minutes, 35 times using the combination of GSP's of SEQ ID NOS: 5 and 6 in the Sequence Listing; a PCR cycle of 94° C. for 1 minute, 53° C. for 1 minute and then 72° C. for 2 minutes, 30 times using the combination of GSP's of SEQ ID NOS: 3 and 6 of the Sequence Listing; And a PCR cycle of 94° C. for 1 minute, 53° C. for 1 minute and then 72° C. for 2 minutes, 30 times using the combination of GSP's of SEQ ID NOS: 4 and 5 of the Sequence Listing to obtain PCR products of 2497 bases, 538 bases, 1257 bases and 1778 bases, respectively (FIG. 1, No. 1-No. 4).

In FIG. 1, NS represents a novel sequence and IS 1 and 2 represent insertion nucleotide sequences 1 and 2.

After amplification of the cDNA's with the primer combinations as those described with respect to FIG. 1, No. 1-No. 4, the resultant PCR products were subjected to electrophoresis using 1.0% agarose gel for the primer combination in No. 1, 1.5% agarose gel for the primer combination in No. 2 and 1.2% agarose gel for both primer combinations in Nos. 3 and 4, respectively, in TAE buffer (Life Technologies) at 75 V for about 1 hour.

The electrophoretic migration patterns are shown in FIGS. 2 and 3. FIG. 2A is the patterns of the PCR products using the primer combination of No. 1. In FIG. 2A) the lanes 1 and 6 are 1 kbp DNA ladder; the lane 2 is the product derived from the lens tissue; the lane 3 is the product derived from the retinal tissue; the lane 4 is the product derived from the brain tissue; and the lane 5 is the product derived from the muscle. FIG. 2B is the patterns of the PCR products using the primer combination of No. 2. In FIG. 2B, the lanes 1 and 6 are 100 b DNA ladder; the lane 2 is the product derived from the lens tissue; the lane 3 is the product derived from the retinal tissue; the lane 4 is the product derived from the brain tissue; and the lane 5 is the product derived from the muscle. FIG. 3A is the patterns of the PCR products by the primer combination in No. 3. In FIG. 3A, the lane 1 is the product derived from the lens tissue; the lane 2 is the product derived from the retinal tissue; the lane 3 is the product derived from the brain tissue; the lane 4 is the product derived from the muscle; and the lane 5 is 1 kbp ladder. FIG. 3B is the patterns of the PCR products by the primer combination in No. 4 and respective lanes are the same as those in FIG. 3A.

As seen from these figures, in the retina, the 3′ side was amplified, while the 5′ side was not amplified. Therefore, it has been shown that the 5′ side sequence is different from that of p94.

FIG. 4 is similar electrophoretic migration patterns of cDNA's amplified with the primer combination in No. 4 of FIG. 1 and digested with the restriction enzymes KpnI (FIG. 4A) and EcoRI (FIG. 4B). The restriction sites are shown in FIG. 1. In FIG. 4A, the lanes 1 and 8 are 1 kbp DNA ladder; the lanes 2 and 3 are the KpnI-digested product derived from the lens; the lanes 4 and 5 are the KpnI-digested product derived from the retina; and the lane 6 and 7 are the KpnI-digested product derived from the muscle. In FIG. 4B, the lanes 1 and 5 are 100 bp DNA ladder; the lane 2 is the EcoRI-digested product derived from the lens; the lane 3 is the EcoRI-digested product derived from the retina; and the lane 4 is the EcoRI-digested product from the muscle. As seen from these figures, the size of the PCR products derived from the lens, retina and muscle tissues are different from one another.

A cDNA amplified with the GSP combination of No. 4 in FIG. 1 was sub-cloned according to a method of TA Cloning™ Kit (Invitrogen).

That is, the PCR product (1 μl) was subjected to ligation together with T4 ligase at 14° C. overnight, followed by transformation into competent cells. The transformed E. coli was plated on a LB plate and incubated at 37° C. overnight. A colony grown on the plate was incubated in a Terrific broth [containing select peptone 140 (11.8 g), yeast extract (23.6 g), dipotassium hydrogen phosphate (9.4 g), and potassium dihydrogen phosphate (2.2 g) per 1 liter, added thereto glycerol (4 ml/l); Life Technologies] at 37° C. overnight.

A plasmid DNA was prepared from the E. coli cultured overnight by using QIAprep Spin Miniprep Kit (QUIAGEN). That is, the broth containing the E. coli was centrifuged at 12,000×g to recover the E. coli, and to this was added buffer solutions P1 and P2 (250 μl), followed by shaking lightly. After standing for 5 minutes, buffer solution N3 (350 μl) was added thereto and the mixture was centrifuged at 12,000×g for 15 minutes. After centrifugation, the supernatant was transferred to a column and centrifuged at 12,000×g for 30 seconds. Further, PB (0.5 ml) was added thereto to wash the column, followed by addition of buffer solution PE (0.75 ml) and centrifugation at 12,000×g for 30 seconds. The plasmid DNA adhered to the column was dissolved in DNase-free water (45 μl) to recover the DNA. The plasmid DNA was digested with the restriction enzyme EcoRI and a positive clone was selected to determine its nucleotide sequence.

(3) 5′ Terminus-cloning

The 5′ terminus sequence was determined by 5′ RACE. The total retinal RNA (4 μg) extracted in the above (1) was subjected to 5′ RACE according to the protocol of 5′ RACE system version 2.0 (Life Technologies). First, the total retinal RNA (4 μg) was subjected to a reverse transcription reaction at 42° C. for 50 minutes and 70° C. for 15 minutes to prepare a 1st strand cDNA. In this reaction, the GSP having the sequence represented by SEQ ID NO: 6 of the Sequence Listing was used as the antisense primer. The 1st strand cDNA thus prepared was purified by GLASS MAX and TdT was added thereto. The resultant cDNA was amplified by PCR. As the sense primer, that of the protocol of the kit was used and the GSP having the sequence represented by SEQ ID NO: 7 of the Sequence Listing was used as the antisense primer. PCR was carried out by repeating a PCR cycle of 94° C. for 1 minute, 55° C. for 1 minute and then 72° C. for 2 minutes, 35 times.

The PCR product was subjected to sub-cloning according the same manner as described in the above (2).

The whole nucleotide sequence was determined based on the above-obtained respective nucleotide sequences at 3′ terminus and 5′ terminus. The whole nucleotide sequence of the CDNA determined is shown in SEQ ID NO: 2 of the Sequence Listing. Further, FIGS. 5 to 10 show comparison of the CDNA sequence (Rt88) and the cDNA sequence (p94) of rat skeleton muscle-specific calpain p94.

In comparison with rat skeleton muscle-specific calpain p94, the DNA sequence of the novel calpain of the present invention differs from p94 in exon 1 and exons 15 and 16. That is, differences were observed in NS region and a part of IS 2 region of p94. In addition, when expression of a mRNA corresponding to this sequence in each eye tissue, brain and muscle tissue in rat was observed, it was expressed specifically in the retina. In view of this, it is considered that the cDNA obtained by the present invention is one of families of calpain specifically expressed in the retina.

Further, an amino acid sequence was deduced from the cDNA sequence thus determined to obtain the amino acid sequence represented by SEQ ID NO: 1 of the Sequence Listing. FIGS. 11 and 12 show comparison of the amino acid sequence (Rt88) with that of p94 represented by the single letter abbreviation.

EXAMPLE 2 Construction of Transfer Vector

GSP's for PCR containing initiation and termination codons respectively were designed based on the cDNA sequence of the novel calpain obtained in the above (2) and (3) in Example 1.

The total retinal RNA extracted in Example 1 (1) was subjected to a reverse transcription reaction using oligo dT primer at 42° C. for 50 minutes and then 70° C. for 15 minutes. Then, the resultant cDNA was amplified by repeating a PCR cycle of 94° C. for 1 minute, 53° C. for 1 minute and 72° C. for 3 minutes, 35 times by using the GSP's represented by SEQ ID NOS: 8 and 4 in the Sequence Listing as the sense and antisense primers, respectively. The PCR product was sub-cloned according to a method of TA Cloning Kit (Invitrogen).

That is, the PCR product (1 μl) was inserted into pCR2.1 by ligation together with T4 ligase at 14° C. overnight. E. coli K12 was transformed with this to obtain a transformant. The transformant was named Escherichia coli K12/Rt88 and have been deposited at National Institute of Bioscience and Human Technology (NIBH), Agency of Industrial Science & Technology, Ministry of International Trade & Industry of 1-3, Higashi 1 chome, Tsukuba-shi, Ibaraki-ken, Japan under the accession number of FERM BP-6237 according to the Budapest treat since Jan. 26, 1998.

EXAMPLE 3 Northern Blotting Technique

Test Method

Northern blotting analysis is composed of (1) extraction of a total RNA from a tissue, (2) electrophoresis of the total RNA and transcription to a membrane, (3) preparation of a probe, (4) hybridization of the probe and the transcribed RNA, and (5) detection of the hybridized RNA.

(1) Extraction of Total RNA From Tissue

According to the same manner as described in Example 1 (1), a total RNA was extracted from each tissue of a 6-week old Sprague-Dawley male rat. Specifically, a total RNA of each tissue was collected and homogenized in TRIzol reagent. Then, chloroform (0.2 ml/ml TRIzol reagent) was added thereto to prepare a suspension and the suspension was allowed to stand at room temperature for 5 minutes. After standing, it was centrifuged at 12,000×g at 4° C. for 15 minutes to separate into a total RNA layer, a protein layer and a DNA layer. Then, The upper layer containing the total RNA was recovered and propyl alcohol (0.5 ml/ml TRIzol reagent) was added thereto to prepare a suspension. After allowing to stand at room temperature for 10 minutes, the suspension was centrifuged at 12,000×g at 4° C. for 10 minutes to precipitate the total RNA. The precipitated total RNA was washed with 75% ethanol and air-dried for 10 minutes to remove ethanol. Finally, it was dissolved in RNase-free water and the concentration was measured at an absorbance A260/280.

(2) Electrophoresis of Total RNA and Transcription to Membrane

Electrophoresis and transcription of the total RNA were carried out according to NorthernMax™ (Ambion). Specifically, first, DEPC treated water (90 ml) was boiled and agarose (1 g) was dissolved therein. After cooling to 50 to 60° C., 10×denaturing gel buffer (10 ml) was added and the mixture was stirred and poured into an electrophoresis apparatus. After solidification, the gel was soaked in 1×MOPS gel running buffer. To the total RNA extracted and purified by the method of the above (1) were added 3-fold amount of formaldehyde load dye and then ethidium bromide solution (1 μl, concentration: 200 g/ml, Life Technologies). Then, the resultant solution was heated at 65° C. for 15 minutes to break the secondary structure of total RNA and then subjected to electrophoresis at a constant voltage of 50 V. After electrophoresis, bands of the total RNA were confirmed by a UV transilluminater and a photograph of the migration pattern was taken by a Polaroid camera. Blotting was carried out in 0.5×TBE buffer (Life Technologies) with a blotting device of TEFCO at a constant voltage of 25 V for 2 hours. After blotting, the membrane was air-dried for 30 minutes and then UV (50 mj) was irradiated with GS GENE linker UV CHANBER (Bio-Rad) to bind the total RNA to the membrane.

(3) Preparation of Probe

For detecting Rt88 mRNA, a probe was prepared. Specifically, first, a partial sequence of Rt88 cDNA was amplified by PCR for detecting Rt88 mRNA. PCR was carried out by adding the template DNA, the full-length Rt88 cDNA (1 ng), primers (0.2 μM, sense primer: SEQ ID NO: 9, and antisense primer: SEQ ID NO: 10) and Taq DNA polymerase (2.5 U, Life Technologies) to 1×PCR buffer [20 mM Tris-HCl (pH 8.4), and 50 mM KCl ], 2 mM MgCl₂ and 0.2 mM dNTP. The PCR cycle of 94° C. for 45 seconds, 58° C. for 45 seconds and then 72° C. for 1 minute was repeated 35 times. The amplified fragment was subjected to ligation to integrate it into a vector containing T7 promoter (pCR2.1) according to the protocol of TA Cloning Kit (Invitrogen). The reaction was carried out at 14° C. for 4 hour or more by using 1×ligation buffer, pCR2.1 (50 ng), the PCR product (10 ng or more) and T4 DNA ligase (4.0 Weiss units). Then, it was transformed into E. coli. Specifically, first, 0.5 M β-mercaptoethanol (2 μl ) was added to one shot competent cells (50 μl ) and, further, a solution after the ligation (1 μl ) was added thereto. The mixture was allowed to stand in ice for 30 minutes. Then, heat treatment was carried out at 42° C. for 30 seconds. Immediately after the heat treatment, the mixture was put back in ice and allowed to stand for 2 minutes. Then, SOC medium (230 μl) was added and the mixture was incubated at 37° C. for 1 hour. Finally, the incubated cells were plated on LB medium (Life Technologies) containing ampicillin (100 μg/ml, Life Technologies), 100 μM IPTG (Life Technologies) and X-gal (40 μg/ml, Life Technologies) and incubated at 37° C. for 16 hours to form colonies. A colony was collected and cultured in Terrific broth (1.2% trypton, 2.4% yeast extract, 17 mM KH₂PO4, and 72 mM K₂HPO₄; Life Technologies). After culturing the colony, the plasmid was recovered from the E. coli by QIAprep Spin Miniprep Kit (QIAGEN). First, the culture broth (3 to 5 ml) was centrifuged and the supernatant was discarded. The remaining E. coli pellet was suspended with buffer P1 (250 μl). Then, to the suspension was added buffer P2 (250 μl), followed by mixing. Further, after 5 minutes, to the resultant mixture was added buffer N3, followed by mixing. Then, the mixture was centrifuged at 13,000×g for 10 minutes and the supernatant was placed on QIAprep Spin Column. Then, the column was centrifuged at 10,000×g for 30 seconds and a solution was removed from the column. Then, buffer PB (500 μl) was added to the column and a solution was removed from the column by centrifugation. Further, buffer PE (750 μl) was added to the column and a solution was removed from the column by centrifugation. Finally, sterilized water (45 μl) was added to the column, followed by allowing to stand for 1 minute. Then, the column was centrifuged and the eluted DNA was recovered. The direction of the sequence integrated was confirmed by PCR.

The cyclic vector propagated in a large amount was cleaved at a site downstream from the probe with a restriction enzyme HindIII (Takara Shuzo) to form a linear vector. The cleaved DNA was purified by removal of proteins by phenol extraction and precipitation with ethanol.

Then, transcription of the probe sequence was carried out by using T7 promoter. The transcription was carried out by using MAX I script™ In Vitro Transcription Kits (Ambion). Specifically, the probe sequence containing the vector (1 μg) was reacted in 1×transcription buffer containing 0.5 mM dNTP, T7 polymerase (20 U) and a ribonuclease inhibitor (10 U) at 37° C. for 1 hour. After transcription, DNase I (2 U). was added and the mixture was reacted at 37° C. for 15 minutes to remove DNA's. Then, the transcription product was subjected to ethanol precipitation to effect concentration and purification of the reaction product.

Further, a labeled material, biotin-binding psoralen, was attached to the transcription product. This was carried out by using BrightStar™ Psoralen-Biotin Nonisotopic Labeling Kit (Ambion).

Psoralen is a material having an affinity to a nucleic acid and, when it is irradiated with a wavelength of 360 nm, it keeps a stable state with binding to a nucleic acid.

Then, the transcribed RNA (500 ng) was irradiated with a wavelength of 360 nm for 45 minutes. After that, n-butanol saturated with distilled water was added thereto to form a suspension and then n-butanol was removed from the suspension by centrifugation. This operation was repeated twice to remove excess psoralen.

(4) Hybridization of Probe and Transcribed RNA

Hybridization was carried out by using NorthernMax™ (Ambion). Specifically, by using a prehybridization/hybridization solution warmed to 68° C. beforehand, the membrane prepared in the above (2) was pre-hybridized for more than 30 minutes. Then, the probe prepared in the above (3) was added thereto at a final concentration of 0.1 nM, and hybridization was carried out at 68° C. for 16 hours. After completion of hybridization, the membrane was washed for 10 minutes twice with a low stringency wash solution #1. Then, the membrane was further washed twice for 15 minutes twice with a high stringency wash solution #2 (warmed at 68° C. beforehand).

(5) Detection of Hybridized RNA

Detection of the hybridized RNA was carried out by using BrightStar™ BioDetect™ Nonisotopic DetectionKit (Ambion). Specifically, first, the membrane was washed for 5 minutes twice with 1×wash buffer. Then, the membrane was further washed for 5 minutes twice with the blocking buffer, followed by shaking for 30 minutes. Then, the membrane was further shaken with the blocking buffer containing a streptavidin-alkali phosphatase conjugate for 30 minutes. Since biotin-binding psoralen was attached to the RNA probe, streptavidin was absorbed by the biotin and the streptavidin-alkali phosphatase conjugate was specifically attached to the RNA probe. Then, the membrane was washed for 15 minutes once with the blocking buffer, for 15 minutes 3 times with 1×wash buffer and for 2 minutes twice with 1×assay buffer. Finally, the membrane was allowed to stand at room temperature for 5 minutes with CDP-Star. The membrane was sandwiched in Bio Max cassette (Kodak) together with Bio Max Light Film (Kodak) and exposed to light. The film exposed to light was developed by soaking in a developing solution for 4 minutes, distilled water for 10 seconds and then a fixer for 4 minutes.

When expression of Rt88 mRNA of rat retinas of various ages was examined, the highest expression amount was recognized in a 6-week old rat. Therefore, retina-specific expression of Rt88 mRNA was examined according to northern blotting technique by using each tissue of a 6-week old rat. As a result, a band was found in the retina and muscle (FIG. 13).

It has been confirmed by using a different probe that the band hybridized to the muscle is skeleton-specific calpain p94, not Rt88. That is, retina-specific expression of Rt88 has been shown by the fact that a band which binds to this probe is detected in the retina.

EXAMPLE 4 Synthesis of Protein

A peptide in which cysteine (Cys) was bound to the peptide of SEQ ID NO: 11 was synthesized according to a solid phase method by using Symphony Multiple Peptide Synthesizer (Protein Technology Inc.) to obtain the peptide as a white powder. Confirmation of the peptide synthesized was carried out by HPLC, mass spectrometry (Kompact MALDI II; Kratos Analystical) and amino acid analysis (System 6300; Beckman).

HPLC

Column: Vydac C18 5μ(inner diameter: 4.8 mm, length: 25 cm; Vydac)

Elution: Eluent A (0.1% trifluoroacetic acid) and Eluent B (acetonitrile containing 0.1% trifluoroacetic acid); Linear gradient elution so that the amount of eluent B was changed from 10% to 40% in 20 minutes.

Flow rate: 1.5 ml/min.

Detection wavelength: 215 nm.

Retention time: about 11 min.

Mass spectrum (M+): Found 2747.0, Theory 2746.1

Amino acid analysis: Arg, 4.77 (5); Asx, 1.95 (2); Cys, 0.34 (1); Glx, 3.97 (4); Gly 2.00 (2); Ile, 0.60 (1); Leu, 0.95 (1); Lys, 0.99 (1); Phe, 1.01 (1); Pro, 1.00 (1); Ser, 0.86 (1); Thr, 0.88 (1); Val, 1.57 (1), wherein the value in the parentheses is the theoretical value. Further, the found values of Cys, Ile and Val are considered to be lower because of hydrolysis.

EXAMPLE 5 Preparation of Polyclonal Antibody

The peptide synthesized in Example 4 was covalently bound to a carrier protein, hemocyanin (KLH), with m-maleinimidobenozyl-N-hydroxysuccinimide ester (MBS). By using this as an antigen, a 10-week old male rabbit (KBL:JW, body weight 2.18 kg) was sensitized by administering a mixture of the antigen (0.50 mg) and complete Freund's adjuvant (CFA) to its back subcutaneously. Further sensitization was carried out on 14 days, 28 days and 42 days after the priming sensitization. Blood samples were collected on 24 days and 38 days after priming sensitization. The above antigen was immobilized on a plate at a concentration of 10 μg/ml and, after blocking, 10⁻¹ to 10⁻⁸ dilutions of a partial blood of the sensitized rabbit were made and they were reacted with the antigen. After washing, each of them was reacted with an anti-rabbit IgG-POD labeled secondary antibody, followed by washing to measure its titer in terms of color development of a substrate solution ABTS. Purification of the polyclonal antibody was carried out by purifying the IgG fraction from the serum of the immunized rabbit with a carrier for purification of an antibody, HiTrap Protein G (Amershan Pharmacia Biotech), and further by using a polypeptide column.

EXAMPLE 6 Production of Rt88 Recombinant Protein Preparation of Competent Cells

E. coli M15 (QIAGEN) (10 μl) was added to LB medium (Life Technologies) (2 ml) containing kanamycin (25 μg/ml) and incubated with shaking at 37° C. overnight. This E. coli M15 solution incubated over night (120 μl) was added to LB medium (120 ml) containing kanamycin (25 μg/ml) and incubated with shaking at 37° C. The incubation was continued until OD₆₀₀ became 0.4. When OD₆₀₀ exceeded 0.4, this culture medium containing M15 was transferred to a tube which had been frozen, and allowed to stand in ice for 10 minutes. Then, the culture medium was centrifuged at 4,000×g at 4° C. for 5 minutes and the supernatant was discarded to recover a pellet. This pellet was re-suspended in cold Tris buffer (15 ml, 10 mM Tris, and 50 mM CaCl₂) and allowed to stand in ice for more than 2 hours. Further, it was centrifuged at 4,000×g at 4° C. for 5 minutes to remove Tris buffer and suspended in Tris buffer containing glycerol (1 ml, 10 mM Tris, 50 mM CaCl₂, and 10% glycerol). Each 50 μl portion thereof was distributed into a tube and stored at −80° C. until it was used.

Preparation of Transformant (Construction of Expression Vector)

A transformant was prepared by using pQE-70 vector contained in QIAexpress Type ATG Kit (QUIAGEN) and M15 based on E. coli K 12 strain. SphI and BamHI restriction sites were provided to 5′ and 3′ termini of Rt88 cDNA, respectively. Further, primers shown by SEQ ID NOS: 12 and 13 were prepared to delete the original termination codon of Rt88. PCR was carried out by using Rt88 cDNA constructed in pCR2.1 cloning vector (Invitrogen) as the template by using the primer shown by SEQ ID NOS: 12 and 13. RCR cycle of 94° C. for 45 seconds, 60° C. for 45 seconds and then 72° C. for 3 minutes was repeated 35 times. First, the PCR product was constructed in pCR2.1 vector and E. coli was transformed to recover a sufficient amount of a plasmid. Then, the plasmid extracted from E. coli was cleaved with SphI (Life Technologies) and BamHI (Life Technologies) and subjected to electrophoresis on 1% agarose gel to separate cleaved Rt88 cDNA's. The Rt88 cDNA was extracted by GENECLEAN II Kit (BIO 101). Similarly, the expression vector, pQE-70 (QIAGEN) vector, was cleaved with SphI (Life Technologies) and BamHI (Life Technologies)

Rt88 cDNA having SphI and BamHI sites (150 ng) and pQE-70 cleaved with SphI and BamHI (50 ng) were subjected to ligation with T4 ligase (Life Technologies) at 14° C. overnight and used for transformation of the competent cell M15. The resultant transformant was named Escherichia coli K12/M15/Rt88 and have been deposited at National Institute of Bioscience and Human Technology (NIBH), Agency of Industrial Science & Technology, Ministry of International Trade & Industry of 1-3, Higashi 1 chome, Tsukuba-shi, Ibaraki-ken, Japan under the accession number of FERM BP-6622 according to the Budapest treat since Jan. 19, 1999.

Introduction of Expression of Recombinant Protein and Purification of Protein

The transformant with pQE-70 vector containing the cDNA was inoculated to LB medium (8 ml) containing kanamycin (25 μg/ml) and ampicillin (100 μg/ml) and incubated at 37° C. overnight. E. coli (7 ml) thus incubated overnight was added to LB medium (200 ml) containing kanamycin (25 μg/ml) and ampicillin (100 μg/ml) and incubated until OD₆₀₀ became to 0.5 to 0.7. When OD₆₀₀ became to 0.5 to 0.7, IPTG was added thereto at a concentration of 1 mM to initiate introduction of expression of a protein. Incubation was ceased 4 hours after initiation of introduction and transferred to a centrifugation tube. The culture medium was centrifuged at 4,000×g at 4° C. for 20 minutes and the supernatant was discarded to recover a pellet. The pellet was disrupted by sonication in Tris buffer (2 ml, Tris-HCl (pH 7.5), 1 mM EDTA, 1 mM EGTA, and 2 mM dithioerythritol) and centrifuged at 10,000×g at 4° C. for 15 minutes to separate into soluble and insoluble proteins. Since Rt88 protein was present in the insoluble protein, the insoluble protein was partly solubilized by 6 M guanidine hydrochloride solution and the guanidine hydrochloride solution was slowly replaced with the above Tris buffer with removing it by a centrifugation tube for dialysis (Ultrafree-CL; Millipore). Since the expressed protein had histidine tag at the C terminus, it was purified by metal chelate affinity chromatography using QIAexpress Type ATG Kit (QUIAGEN). The solvent-replaced solution (4 ml) and 50% NiNTA (1 ml) was mixed with shaking at 4° C. for 60 minutes. This was inserted in a column (QIAexpress Type ATG Kit; QIAGEN) from its upper end and then a solution was allowed to flow out by removing the cap at the lower end. The column was washed twice with a wash buffer (4 ml, 50 mM NaH₂PO₄ (pH 8.0), 300 mM NaCl, and 20 mM imidazole) and eluted 8 times with an eluting buffer (0.5 ml, 50 mM NaH₂PO₄ (pH 8.0), 300 mM NaCl, and 250 mM imidazole). Purification of the desired protein was confirmed by subjecting the eluted fraction to immunoblotting technique with the Rt88 antibody (polyclonal antibody) prepared in Example 4 and PentaHis antibody (QIAGEN). That is, first, SDS polyacrylamide gel electrophoresis (SDS-PAGE) was carried out in an electrophoresis buffer (25 mM Tris, 192 mM glycine, and 0.1% SDS; pH 8.3) at a constant voltage of 150 V for 90 minutes by using 10% polyacryalamide gel (TEFCO). After electrophoresis, the proteins separated in the gel were transcribed on Immobilon-P membrane (PVDF; Millipore) in an ice-cooled transcription buffer (25 mM Tris, 192 mM glycine, 20% methanol, and 0.1% SDS; pH 8.3) at a constant voltage of 100 V for 70 minutes with a buffer tank type transcription apparatus according to the method described by Towbin et al. (Proc. Natl. Acad. Sci. USA, 76, 4350-4354, 1979). The transcribed membrane was subjected to blocking in Tris buffered physiological saline (TBS, 20 mM Tris-HCl (pH 7.5), and 500 mM sodium chloride) for 30 minutes, followed by washing for 5 minutes twice with TBS containing 0.05% Tween 20 (Bio-Rad) (TTBS). The membrane was incubated with the Rt88 antibody prepared in Example 4 overnight to react the antibody with the proteins on the membrane. Since the expressed protein has histidine tag at the C terminus, by utilizing this, a monoclonal antibody (PentaHis antibody; QIAGEN) having reactivity with 5×His was also used. After completion of the reaction, the membrane was washed for 5 minutes twice with TTBS. Then, the membrane was incubated in a solution of a secondary antibody, alkali phosphatase-labeled goat anti-rabbit IgG (Bio-Rad) for the Rt88 antibody, or alkali phosphatase-labeled goat anti-mouse antibody for PentaHis antibody, diluted 3,000 times with TTBS containing 1% BSA. After completion of the reaction, the membrane was washed for 5 minutes twice with TTBS, and then for 5 minutes twice with TBS. A protein reacted with the Rt88 antibody in the proteins separated on the membrane was detected by using AP Conjugated Substrate Kit (Bio-Rad). Further, the same procedure was repeated by using a transformant with a vector having no inserted gene, i.e., Rt88 gene. As a result, in the protein before purification, no band was detected from the transformant with the vector having no Rt88 gene by the Rt88 antibody, while a band was recongized at about 88 kDa in the insoluble protein from the transformant with the vector containing Rt88 gene by the Rt88 antibody (FIG. 14). In view of this, the protein reactive with Rt88 antibody was confirmed to be that derived from Rt88. Further, the protein containing Rt88 was purified by metal chelate affinity chromatography and Rt88 protein was detected by the antibody according to the same manner as described above. As a result, a single band was recognized at about 88 kDa by the Rt88 antibody. A band was also detected at the same size by PentaHis antibody (FIG. 15). Therefore, expression and purification of Rt88 recombinant protein was confirmed.

EXAMPLE 7 Isolation and Purification of Rt88 From Rat Retina

A 6-week old Sprague-Dawlay rat was slaughtered and the eyes were removed. The retinal tissue was collected in an ice-cooled buffer (20 mM Tris-HCl (pH 7.5), 1 mM EDTA, 1 mM EGTA, 2 mM dithioerythritol, and 0.1 mM leupeptin). The retinal tissue was homogenized in the above buffer in ice by sonication and centrifuged at 13,000×g at 4° C. for 15 minutes to prepare a soluble protein. The concentration of the soluble protein contained in the resultant solution was determined by using BCA protein Assay Kit (PIERCE). A solution containing a predetermined concentration of bovine serum albumin (BSA; Sigma) was used as a standard solution. The retinal soluble protein solution thus determined was dried under reduced pressure, dissolved in a sample buffer (50 mM Tris-HCl (pH 6.8), 8% glycerol, 1.6% sodium dodecyl sulfate (SDS), 4% 2-mercaptoethanol, and 0.002% Boromophenol Blue) and subjected to heat treatment at 100° C. for 5 minutes. The retinal soluble protein (40 μg) was subjected to SDS polyacrylamide gel electrophoresis (SDS-PAGE) according to the method described by Laemmli et al. (Nature 227, 680-685, 1970) in an electrophoresis buffer (25 mM Tris, 192 mM glycine, and 0.1% SDS; pH 8.3) at a constant voltage of 150 V for 90 minutes by using 8% acrylamide gel (TEFCO). After electrophoresis,.according to the above method described by Towbin et al., the proteins separated in the gel was transcribed on Immobilon-P membrane (PVDF; Millipore) in an ice-cooled transcription buffer (25 mM Tris, 192 mM glycine, 20% methanol, and 0.1% SDS; pH 8.3) at a constant voltage of 100 V for 70 minutes by using a buffer tank type transcription apparatus. The transcribed membrane was subjected to blocking in Tris buffered physiological saline (TBS, 20 mM Tris-HCl (pH 7.5), and 500 mM sodium chloride) for 30 minutes. The membrane was washed for 5 minutes twice with TBS containing 0.05% Tween 20 (Bio-Rad) (TTBS) and incubated with the antigen against Rt88 prepared in Example 4 overnight to react it with the proteins on the membrane. After completion of the reaction, the membrane was washed for 5 minutes twice with TTBS and incubated with a solution of alkali phosphatase labeled goat anti-rabbit IgG (Bio-Rad) and diluted 3,000 times with TTBS containing 1% BSA for 1 hour. After completion of the reaction, the membrane was washed for 5 minutes twice with TTBS and then for 5 minutes twice with TBS. Then, a protein reactive with the Rt88 antibody in the retinal soluble protein separated on the membrane with AP Conjugated Substrate Kit (Bio-Rad). As a result, a protein which were considered to be Rt88 of a molecular weight of about 90 kDa was detected.

The resultant retinal soluble protein solution was fractionated by HPLC with an anion exchange resin TSKgel DEAE-5PW (Tosoh). The protein solution (20 mg) was fractionated by developing the protein solution with the above buffer at a flow rate of 1 ml/minute to absorb the protein on the resin, eluting the absorbed protein with the buffer by increasing its sodium chloride concentration from 0 mM to 500 mM linearly to separate the protein. All the fractions thus separated were activated and the casein decomposing activity detected by zymography technique. Each fraction (1,000 μl) was concentrated (to 100 μl) and the concentrate (20 μl), as a protein solution, was dissolved in a sample buffer (50 mM Tris-HCl (pH 6.8), 8% glycerol, 4% 2-mercaptoethanol, and 0.002% Bromophenol Blue) under non-denaturation reducing conditions and separated by electrophoresis using 7% acrylamide gel (TEFCO) containing 0.1% casein in ice at a constant voltage of 125 V for 150 minutes. As an electrophoresis buffer, 25 mM Tris and 192 mM glycine (pH 8.3) were used. After separation, the gel was incubated in a buffer containing calcium (20 mM Tris-HCl (pH 7.4), 1 mM calcium chloride, and 10 mM dithiothreitol) for 20 hours to activate the calcium dependent protease in the gel. The incubated gel was stained with 0.05% Coomassie Brilliant Blue R-250 (Bio-Rad) (10% acetic acid and 40% methanol) and the protease activity was detected as casein decomposition activity. As a result, casein decomposing activity was detected in some fractions. Further, these fractions having casein decomposing activity were subjected to SDS-PAGE and transcription on the membrane according to the same manner as described above to examine the reactivity with the Rt88 antibody prepared in Example 4. As a result, a reactive fraction was obtained at about molecular weight of about 90 kDa.

EXAMPLE 8 Rt88 Gene Transfer

The process for construction of a vector is roughly divided into the following eight steps. (1) Extraction of total RNA and treatment with DNase I; (2) RT-PCR for amplification of Rt88 cDNA; (3) Integration into a plasmid and transformation of E. coli; (4) Purification of the plasmid; (5) Cleavage of Rt88 sequence from the plasmid and cut out from the gel; (6) Cleavage of vector pRc/CMV and dephosphorylation treatment for expression in human 293 cells; (7) Integration of the sequence cut out in the above step (5) into the vector dephosphorylated in the above step (6); and (8) Purification of the plasmid and confirmation of the orientation. Details are as follows.

(1) According to the same manner as that described in Example 1 (1), extraction of a total RNA and DNase treatment were carried out by using a 6-week old Sprague-Dawley male rat.

(2) The DNase I-treated total RNA was subjected to a reverse transcription reaction with oligo dT primer under conditions of 42° C. for 50 minutes and 70° C. for 15 minutes. Then, the resultant cDNA was amplified by repeating a PCR cycle of 94° C. for 1 minute, 53° C. for 1 minute and then 72° C. for 3 minutes, 35 times.

(3) According to the same manner as that described in Example 1 (2), integration into a plasmid and transformation of E. coli were carried out.

(4) According to the same manner as that described in Example 1 (2), the plasmid was purified.

(5) pCR 2.1 (INVITROGEN) containing Rt88 cDNA was cleaved with restriction enzyme BstXI (Takara Shuzo) to extract only the cDNA of Rt88. Electrophoresis was carried out using 1% agarose gel and the band of Rt88 cDNA was cut out of the gel. Then, Rt88 cDNA was recovered from the gel by using EASYRAP™ Ver. 2 (Takara Shuzo). Further, ethanol precipitation was carried out to concentrate it.

(6) Vector pRc/CMV (Invitrogen) for expression in 293 cells derived from human fetal kidney was also cleaved with restriction enzyme BstXI (Takara Shuzo). According to the same manner as that described in the above (5), the vector was recovered-from the gel. The vector was further dephosphorylated. Specifically, the vector (2 μg) and calf intestin alkali phosphatase (CIAP; 120 U; STRATAGENE) were reacted in 1×buffer (50 mM Tris-HCl (pH 8.0), 0.1 mM EDTA) at 37° C. for 15 minutes and 50° C. for 15 minutes. After completion of the reaction, purification and concentration were carried out by phenol treatment and ethanol precipitation.

(7) According to the same manner as described in the above Example 1 (2), Rt88 was integrated into the vector obtained in the above (6) and used for transformation.

(8) According to the same manner as described in the above Example 1 (2), the plasmid was purified from the resultant transformant. The orientation of Rt88 integrated in the plasmid was confirmed by cleavage with restriction enzyme KpnI (Takara Shuzo), followed by electrophoresis.

Gene Transfer

293 Cells derived from human fetal kidney were sub-cultured in a cell culture dish of 6 cm diameter at a concentration of 50%, 24 hours prior to gene transfer. Lipofectin reagent (10 μl, Life Technologies) was dissolved in OPTI-MEM I medium (200 μl) and allowed to stand at room temperature for 45 minutes to obtain Solution A. On the other hand, an expression vector DNA (2 μg) was dissolved in OPTI-MEM I (200 μl) to obtain Solution B. Solutions A and B were mixed and allowed to stand at room temperature for 15 minutes. The cells in the 6 cm dish was washed with serum-free Dulbecco modified MEM medium and to this were added the mixture of Solutions A and B and OPTI-MEM I medium (1.6 ml), followed by incubation at 37° C. for 6 hours in a 5% CO₂ incubator. The medium was removed and Dulbecco modified MEM medium containing 10% fetal bovine serum (4 ml) was added. The cells were incubated at 37° C. for 48 hours in a 5% CO₂ incubator. The cells were diluted 1:5 in a 10 cm dish, sub-cultured and cultured in Dulbecco modified MEM medium containing G418 (400 μg/ml; GENETICIN; Life Technologies) and 10% fetal bovine serum so that only the gene transferred cells survived. Selection of the cells was continued until only the transformed cells were remained. Then, the cells were sub-cultured in a 6 cm cell culture dish and cultured in Dulbecco modified MEM medium containing G418 (200 μg/ml) and 10% fetal bovine serum. When the cells reached confluent growth, the medium was removed and the cells were washed twice with a phosphate buffer, followed by addition of TRIzol reagent (1 ml; Life Technologies) and standing at room temperature for 10 minutes. The cells were transferred to a homogenizer and homogenized. Then, the homogenate was transferred to a 1.5 ml tube. Chloroform (0.2 ml) was added thereto and mixed. The mixture was allowed to stand at room temperature for 3 minutes and centrifuged at 12,000×g at 4° C. for 15 minutes to recover an aqueous layer. To this layer was added 2-isopropanol (0.5 ml) and mixed. The mixture was allowed to stand at room temperature for 10 minutes and centrifuged at 12,000×g at 4° C. for 10 minutes. The resultant precipitate was suspended in 75% ethanol (1 ml) and further centrifuged at 12,000×g at 4° C. for 5 minutes to recover the precipitate. This precipitate was dissolved in an appropriate amount of water. Then, it was treated with DNase I (Life Technologies) to obtain a total RNA. The total RNA was subjected to a reverse transcription reaction with oligo dT primer (Life Technologies) at 42° C. for 50 minutes and 70° C. for 15 minutes. The resultant cDNA was amplified by repeating a PCR cycle of 94° C. for 1 minute, 58° C. for 1 minute and then 72° C. for 3 minutes, 35 times using GSP's of SEQ ID NOS: 4 and 8. The PCR reaction was carried out in a reaction mixture (50 μl) containing 20 mM Tris-HCl, 50 mM KCl, 0.2 mM dNTP, 2 mM MgCl2, 2.5U Taq DNA polymerase and 0.2 μM primers. The PCR product was subjected to electrophoresis using 1.2% agarose gel in TAE buffer (Life Technologies) at 75 V for about 1 hour. As a result, a band of the amplified cDNA was recognized at the expected size (FIG. 16). On the other hand, no amplification was observed in 293 cells which did not contain Rt88 gene, i.e., contained only the vector. Therefore, it has been shown that Rt88 mRNA is expressed in 293 cells to which Rt88 gene was transferred and normal transcription is taken place in the gene transferred cells.

SEQUENCE LISTING FREE TEXT

SEQ ID NO: 2 is cDNA (61-1240)/mRNA. SEQ ID NO: 3 to SEQ ID NO: 10 and SEQ ID NO: 12 to SEQ ID NO: 12 are primers. SEQ ID NO: 11 is an antigen.

16 1 757 PRT Sprague-Dawley rat 1 Met Pro Tyr Leu Leu Pro Gly Phe Phe Cys Asp Arg Val Ile Arg Glu 1 5 10 15 Arg Asp Arg Arg Asn Gly Glu Gly Thr Val Ser Gln Pro Leu Lys Phe 20 25 30 Glu Gly Gln Asp Phe Val Val Leu Lys Gln Arg Cys Leu Ala Gln Lys 35 40 45 Cys Leu Phe Glu Asp Arg Val Phe Pro Ala Gly Thr Gln Ala Leu Gly 50 55 60 Ser His Glu Leu Ser Gln Lys Ala Lys Met Lys Ala Ile Thr Trp Lys 65 70 75 80 Arg Pro Lys Glu Ile Cys Glu Asn Pro Arg Phe Ile Ile Gly Gly Ala 85 90 95 Asn Arg Thr Asp Ile Cys Gln Gly Asp Leu Gly Asp Cys Trp Phe Leu 100 105 110 Ala Ala Ile Ala Cys Leu Thr Leu Asn Glu Arg Leu Leu Phe Arg Val 115 120 125 Ile Pro His Asp Gln Ser Phe Thr Glu Asn Tyr Ala Gly Ile Phe His 130 135 140 Phe Gln Phe Trp Arg Tyr Gly Asp Trp Val Asp Val Val Ile Asp Asp 145 150 155 160 Cys Leu Pro Thr Tyr Asn Asn Gln Leu Val Phe Thr Lys Ser Asn His 165 170 175 Arg Asn Glu Phe Trp Ser Ala Leu Leu Glu Lys Ala Tyr Ala Lys Leu 180 185 190 His Gly Ser Tyr Glu Ala Leu Lys Gly Gly Asn Thr Thr Glu Ala Met 195 200 205 Glu Asp Phe Thr Gly Gly Val Thr Glu Phe Phe Glu Ile Lys Asp Ala 210 215 220 Pro Ser Asp Met Tyr Lys Ile Met Arg Lys Ala Ile Glu Arg Gly Ser 225 230 235 240 Leu Met Gly Cys Ser Ile Asp Asp Gly Thr Asn Met Thr Tyr Gly Thr 245 250 255 Ser Pro Ser Gly Leu Asn Met Gly Glu Leu Ile Ala Arg Met Val Arg 260 265 270 Asn Met Asp Asn Ser Leu Leu Arg Asp Ser Asp Leu Asp Pro Arg Ala 275 280 285 Ser Asp Asp Arg Pro Ser Arg Thr Ile Val Pro Val Gln Tyr Glu Thr 290 295 300 Arg Met Ala Cys Gly Leu Val Lys Gly His Ala Tyr Ser Val Thr Gly 305 310 315 320 Leu Glu Glu Ala Leu Phe Lys Gly Glu Lys Val Lys Leu Val Arg Leu 325 330 335 Arg Asn Pro Trp Gly Gln Val Glu Trp Asn Gly Ser Trp Ser Asp Gly 340 345 350 Trp Lys Asp Trp Ser Phe Val Asp Lys Asp Glu Lys Ala Arg Leu Gln 355 360 365 His Gln Val Thr Glu Asp Gly Glu Phe Trp Met Ser Tyr Asp Asp Phe 370 375 380 Val Tyr His Phe Thr Lys Leu Glu Ile Cys Asn Leu Thr Ala Asp Ala 385 390 395 400 Leu Glu Ser Asp Lys Leu Gln Thr Trp Thr Val Ser Val Asn Glu Gly 405 410 415 Arg Trp Val Arg Gly Cys Ser Ala Gly Gly Cys Arg Asn Phe Pro Asp 420 425 430 Thr Phe Trp Thr Asn Pro Gln Tyr Arg Leu Lys Leu Leu Glu Glu Asp 435 440 445 Asp Asp Pro Asp Asp Ser Glu Val Ile Cys Ser Phe Leu Val Ala Leu 450 455 460 Met Gln Lys Asn Arg Arg Lys Asp Arg Lys Leu Gly Ala Asn Leu Phe 465 470 475 480 Thr Ile Gly Phe Ala Ile Tyr Glu Val Pro Lys Glu Met His Gly Asn 485 490 495 Lys Gln His Leu Gln Lys Asp Phe Phe Leu Tyr Asn Ala Ser Lys Ala 500 505 510 Arg Ser Lys Thr Tyr Ile Asn Met Arg Glu Val Ser Gln Arg Phe Arg 515 520 525 Leu Pro Pro Ser Glu Tyr Val Ile Val Pro Ser Thr Tyr Glu Pro His 530 535 540 Gln Glu Gly Glu Phe Ile Leu Arg Val Phe Ser Glu Lys Arg Asn Leu 545 550 555 560 Ser Glu Glu Ala Glu Asn Thr Ile Ser Val Asp Arg Pro Val Pro Arg 565 570 575 Pro Gly His Thr Asp Gln Glu Ser Glu Glu Gln Gln Gln Phe Arg Asn 580 585 590 Ile Phe Arg Gln Ile Ala Gly Asp Asp Met Glu Ile Cys Ala Asp Glu 595 600 605 Leu Lys Asn Val Leu Asn Thr Val Val Asn Lys His Lys Asp Leu Lys 610 615 620 Thr Gln Gly Phe Thr Leu Glu Ser Cys Arg Ser Met Ile Ala Leu Met 625 630 635 640 Asp Thr Asp GLy Ser Gly Arg Leu Asn Leu Gln Glu Phe His His Leu 645 650 655 Trp Lys Lys Ile Lys Ala Trp Gln Lys Ile Phe Lys His Tyr Asp Thr 660 665 670 Asp His Ser Gly Thr Ile Asn Ser Tyr Glu Met Arg Asn Ala Val Asn 675 680 685 Asp Ala Gly Phe His Leu Asn Ser Gln Leu Tyr Asp Ile Ile Thr Met 690 695 700 Arg Tyr Ala Asp Lys His Met Asn Ile Asp Phe Asp Ser Phe Ile Cys 705 710 715 720 Cys Phe Val Arg Leu Glu Gly Met Phe Arg Ala Phe His Ala Phe Asp 725 730 735 Lys Asp Gly Asp Gly Ile Ile Lys Leu Asn Val Leu Glu Trp Leu Gln 740 745 750 Leu Thr Met Tyr Ala 755 2 2353 DNA Sprague-Dawley rat cDNA (61-1240)/mRNA 2 tcaggcctgg gctgagggtg cagcaggaga ggccgcaggg aaggccgggt tccactgctc 60 gtcatc atg ccc tac ctg ctg ccg gga ttc ttc tgt gac aga gtg atc 108 aga gaa agg gac agg aga aat gga gag ggc acc gtc tca cag cct ctc 156 aag ttt gag ggg cag gat ttt gtc gtt ctc aaa caa cgg tgt ctg gct 204 cag aag tgc ctc ttt gaa gat cga gtc ttc cca gca ggt aca cag gcc 252 ctt ggc tca cat gag ctg agc cag aaa gcc aag atg aag gcc atc act 300 tgg aag agg cca aag gaa att tgt gag aat ccc cga ttt atc att ggt 348 gga gcc aac agg act gac atc tgc caa gga gat cta ggg gac tgc tgg 396 ttt ctt gca gcc att gcc tgt ctg acc ctg aat gag cga ctg ctt ttc 444 cga gtt ata cct cat gat caa agt ttc act gaa aac tac gca ggg atc 492 ttc cac ttc cag ttc tgg cgc tat gga gac tgg gta gat gtg gtt att 540 gac gac tgt ctg ccg aca tac aac aac cag ctg gtc ttc acc aaa tcc 588 aac cac cgc aat gag ttc tgg agt gct cta ctg gag aaa gca tat gcc 636 aag ctc cat ggt tcc tat gaa gct ctg aaa ggt ggg aac acc aca gaa 684 gcc atg gag gac ttc aca gga ggg gtg aca gag ttt ttt gag atc aag 732 gat gct ccg agt gac atg tac aag atc atg agg aaa gct atc gag aga 780 ggc tcc ctc atg ggc tgc tcc att gat gat ggc acc aac atg act tat 828 gga acc tct cct tct ggt ctg aac atg ggg gaa ttg att gcg cgg atg 876 gtg aga aat atg gat aac tcg ctg ctc aga gac tca gac ctg gac ccc 924 agg gcc tca gat gac aga ccg tca cgg aca att gtt ccg gtg cag tat 972 gaa aca aga atg gcc tgt gga ctg gtg aaa ggg cac gcc tat tca gtc 1020 act ggg ctg gag gag gcc ctg ttc aaa ggc gag aag gtg aag ctg gtg 1068 cgg ctg cgg aac ccc tgg ggc cag gtg gag tgg aac ggc tct tgg agt 1116 gat ggt tgg aag gac tgg agc ttt gtg gac aaa gac gag aag gcc cgt 1164 ctg cag cac cag gtc acc gag gat gga gag ttc tgg atg tca tat gat 1212 gac ttt gtc tac cat ttc aca aag ctg gag atc tgc aac ctc aca gct 1260 gat gcc ctg gag tcc gat aag ctt cag acc tgg aca gtg tct gta aat 1308 gag ggc cgc tgg gtg agg ggc tgt tct gct gga ggc tgc cgg aac ttc 1356 cca gac act ttc tgg acc aac ccg cag tac cgt ctc aag ctc ctg gag 1404 gag gat gat gac cct gat gac tct gag gtg att tgc agc ttc ctc gtg 1452 gct ctg atg cag aaa aat cgg cgc aag gac cgg aag ctg ggg gcc aac 1500 ctc ttc acc att ggc ttc gct atc tac gag gtt ccc aaa gag atg cac 1548 ggg aat aag caa cac ctg cag aag gac ttc ttc ttg tac aat gcc tcc 1596 aag gcc agg agc aaa acc tac atc aac atg cgg gag gtg tcc cag cgc 1644 ttc cgc ctg ccg ccc agc gag tat gtc att gtc ccc tcc act tac gag 1692 ccc cat cag gag ggg gaa ttc atc ctc cgg gtc ttc tct gaa aag agg 1740 aat ctc tct gag gaa gct gag aat aca atc tct gtg gac cgg cca gtg 1788 cca cgg cct ggc cac aca gac cag gag agt gag gag cag cag caa ttc 1836 cgg aac atc ttc agg cag att gca ggc gac gac atg gag atc tgt gcg 1884 gat gaa ctc aag aat gtc ctt aat acg gtg gtg aac aaa cac aag gac 1932 ctg aag aca caa ggg ttc act ctg gag tcc tgc aga agc atg ata gct 1980 ctc atg gat aca gat ggc tct ggg aga ctg aat ctt caa gag ttc cat 2028 cac ctc tgg aaa aag atc aag gcc tgg cag aaa atc ttc aaa cac tat 2076 gac act gac cat tct ggt acc atc aat agc tat gag atg cga aat gca 2124 gtc aat gat gca ggc ttc cat ctc aac agc caa ctc tat gac atc atc 2172 acc atg cgc tac gca gac aaa cac atg aac atc gac ttt gac agc ttc 2220 atc tgc tgc ttc gtc agg ctg gaa ggg atg ttc aga gct ttt cac gca 2268 ttt gac aag gat gga gat ggc atc atc aaa ctg aac gta ctt gag tgg 2316 ctg cag ctt acc atg tat gcc tga 2340 accagatgac ctc 2353 3 30 DNA Artificial Sequence primer 3 cttccaaagt tgcctgccat gccgaccgtt 30 4 30 DNA Artificial Sequence primer 4 gaggtcatct ggttcaggca tacatggtaa 30 5 26 DNA Artificial Sequence primer 5 ggtgacagag ttttttgaga tcaagg 26 6 30 DNA Artificial Sequence primer 6 gatctccagc tttgtgaaat ggtagacaaa 30 7 30 DNA Artificial Sequence primer 7 tgagcagcga gttatccata tttctcacca 30 8 30 DNA Artificial Sequence primer 8 tcatcatgcc ctacctgctg ccgggattct 30 9 30 DNA Artificial Sequence primer 9 gatgaaggcc atcacttgga agaggccaaa 30 10 30 DNA Artificial Sequence primer 10 agaggttcca taagtcatgt tggtgccatc 30 11 22 PRT Artificial Sequence antigen 11 Arg Val Ile Arg Glu Arg Asp Arg Arg Asn Gly Glu Gly Thr Val Ser 5 10 15 Gln Pro Leu Lys Phe Glu 20 12 23 DNA Artificial Sequence primer 12 ctgctcgtca gcatgcccta cct 23 13 26 DNA Artificial Sequence primer 13 gtcatctggt ggatccatac atggta 26 14 23 PRT Artificial Sequence antigen 14 Cys Arg Val Ile Arg Glu Arg Asp Arg Arg Asn Gly Glu Gly Thr Val Ser 5 10 15 Gln Pro Leu Lys Phe Glu 20 15 821 PRT Norway rat p94 protein 15 Met Pro Thr Val Ile Ser Pro Thr Val Ala Pro Arg Thr Gly Ala Glu 1 5 10 15 Pro Arg Ser Pro Gly Pro Val Pro His Pro Ala Gln Gly Lys Thr Thr 20 25 30 Glu Ala Gly Gly Gly His Pro Gly Gly Ile Tyr Ser Ala Ile Ile Ser 35 40 45 Arg Asn Phe Pro Ile Ile Gly Val Lys Glu Lys Thr Phe Glu Gln Leu 50 55 60 His Lys Lys Cys Leu Glu Lys Lys Val Leu Tyr Leu Asp Pro Glu Phe 65 70 75 80 Pro Pro Asp Glu Thr Ser Leu Phe Tyr Ser Gln Lys Phe Pro Ile Gln 85 90 95 Phe Val Trp Lys Arg Pro Pro Glu Ile Cys Glu Asn Pro Arg Phe Ile 100 105 110 Ile Gly Gly Ala Asn Arg Thr Asp Ile Cys Gln Gly Asp Leu Gly Asp 115 120 125 Cys Trp Leu Leu Ala Ala Ile Ala Cys Leu Thr Leu Asn Glu Arg Leu 130 135 140 Leu Phe Arg Val Ile Pro His Asp Gln Ser Phe Thr Glu Asn Tyr Ala 145 150 155 160 Gly Ile Phe His Phe Gln Phe Trp Arg Tyr Gly Asp Trp Val Asp Val 165 170 175 Val Ile Asp Asp Cys Leu Pro Thr Tyr Asn Asn Gln Leu Val Phe Thr 180 185 190 Lys Ser Asn His Arg Asn Glu Phe Trp Ser Ala Leu Leu Glu Lys Ala 195 200 205 Tyr Ala Lys Leu His Gly Ser Tyr Glu Ala Leu Lys Gly Gly Asn Thr 210 215 220 Thr Glu Ala Met Glu Asp Phe Thr Gly Gly Val Thr Glu Phe Phe Glu 225 230 235 240 Ile Lys Asp Ala Pro Ser Asp Met Tyr Lys Ile Met Arg Lys Ala Ile 245 250 255 Glu Arg Gly Ser Leu Met Gly Cys Ser Ile Asp Asp Gly Thr Asn Met 260 265 270 Thr Tyr Gly Thr Ser Pro Ser Gly Leu Asn Met Gly Glu Leu Ile Ala 275 280 285 Arg Met Val Arg Asn Met Asp Asn Ser Leu Leu Arg Asp Ser Asp Leu 290 295 300 Asp Pro Arg Ala Ser Asp Asp Arg Pro Ser Arg Thr Ile Val Pro Val 305 310 315 320 Gln Tyr Glu Thr Arg Met Ala Cys Gly Leu Val Lys Gly His Ala Tyr 325 330 335 Ser Val Thr Gly Leu Glu Glu Ala Leu Phe Lys Gly Glu Lys Val Lys 340 345 350 Leu Val Arg Leu Arg Asn Pro Trp Gly Gln Val Glu Trp Asn Gly Ser 355 360 365 Trp Ser Asp Gly Trp Lys Asp Trp Ser Phe Val Asp Lys Asp Glu Lys 370 375 380 Ala Arg Leu Gln His Gln Val Thr Glu Asp Gly Glu Phe Trp Met Ser 385 390 395 400 Tyr Asp Asp Phe Val Tyr His Phe Thr Lys Leu Glu Ile Cys Asn Leu 405 410 415 Thr Ala Asp Ala Leu Gln Ser Asp Lys Leu Gln Thr Trp Thr Val Ser 420 425 430 Val Asn Glu Gly Arg Trp Val Arg Gly Cys Ser Ala Gly Gly Cys Arg 435 440 445 Asn Phe Pro Asp Thr Phe Trp Thr Asn Pro Gln Tyr Arg Leu Lys Leu 450 455 460 Leu Glu Glu Asp Asp Asp Pro Asp Asp Ser Glu Val Ile Cys Ser Phe 465 470 475 480 Leu Val Ala Leu Met Gln Lys Asn Arg Arg Lys Asp Arg Lys Leu Gly 485 490 495 Ala Asn Leu Phe Thr Ile Gly Phe Ala Ile Tyr Glu Val Pro Lys Glu 500 505 510 Met His Gly Asn Lys Gln His Leu Gln Lys Asp Phe Phe Leu Tyr Asn 515 520 525 Ala Ser Lys Ala Arg Ser Lys Thr Tyr Ile Asn Met Arg Glu Val Ser 530 535 540 Gln Arg Phe Arg Leu Pro Pro Ser Glu Tyr Val Ile Val Pro Ser Thr 545 550 555 560 Tyr Glu Pro His Gln Glu Gly Glu Phe Ile Leu Arg Val Phe Ser Glu 565 570 575 Lys Arg Asn Leu Ser Glu Glu Ala Glu Asn Thr Ile Ser Val Asp Arg 580 585 590 Pro Val Lys Lys Lys Lys Asn Lys Pro Ile Ile Phe Val Ser Asp Arg 595 600 605 Ala Asn Ser Asn Lys Glu Leu Gly Val Asp Gln Glu Ala Glu Glu Gly 610 615 620 Lys Asp Lys Thr Gly Pro Asp Lys Gln Gly Glu Ser Pro Gln Pro Arg 625 630 635 640 Pro Gly His Thr Asp Gln Glu Ser Glu Glu Gln Gln Gln Phe Arg Asn 645 650 655 Ile Phe Arg Gln Ile Ala Gly Asp Asp Met Glu Ile Cys Ala Asp Glu 660 665 670 Leu Lys Asn Val Leu Asn Thr Val Val Asn Lys His Lys Asp Leu Lys 675 680 685 Thr Gln Gly Phe Thr Leu Glu Ser Cys Arg Ser Met Ile Ala Leu Met 690 695 700 Asp Thr Asp Gly Ser Gly Arg Leu Asn Leu Gln Glu Phe His His Leu 705 710 715 720 Trp Lys Lys Ile Lys Ala Trp Gln Lys Ile Phe Lys His Tyr Asp Thr 725 730 735 Asp His Ser Gly Thr Ile Asn Ser Tyr Glu Met Arg Asn Ala Val Asn 740 745 750 Asp Ala Gly Phe His Leu Asn Ser Gln Leu Tyr Asp Ile Ile Thr Met 755 760 765 Arg Tyr Ala Asp Lys His Met Asn Ile Asp Phe Asp Ser Phe Ile Cys 770 775 780 Cys Phe Val Arg Leu Glu Gly Met Phe Arg Ala Phe His Ala Phe Asp 785 790 795 800 Lys Asp Gly Asp Gly Ile Ile Lys Leu Asn Val Leu Glu Trp Leu Gln 805 810 815 Leu Thr Met Tyr Ala 820 16 3138 DNA Norway rat DNA encoding p94 protein 16 ttttcttttt ttcctctggc aagcctgctg ctggtaggca cccccaggta gaagctgcgt 60 ctaaatcctt tattgcctct tcctcaggaa tacctattgc tctagggtca tagttcacct 120 atttaagctg gtcagaggcc agccaatttt ctgataggat ttaaactttg aagagactgt 180 agccattttt ttcctcagat gacagaatca cttcaacttc cactttgtaa tcgcttcctt 240 tccttgaagg tagctgaatc ttgttttctt taaaaacgtc ttccttccaa agttgcctgc 300 catgccgacc gttattagtc caactgtggc cccaaggaca ggagctgagc ccaggtcccc 360 agggccagtt cctcacccag ctcaaggcaa gaccactgag gctggaggtg gacacccggg 420 tggcatctat tcagccatca tcagccgcaa ttttccgatc attggtgtga aagagaagac 480 attcgagcag ctccacaaga agtgcctaga gaagaaagtt ctttacctgg atcccgagtt 540 cccaccggat gagacctctc tcttttacag ccagaagttc cccatccagt tcgtctggaa 600 gagacctccg gaaatttgtg agaatccccg atttatcatt ggtggagcca acaggactga 660 catctgccaa ggagatctag gggactgctg gcttcttgca gccattgcct gtctgaccct 720 gaatgagcga ctgcttttcc gagttatacc tcatgatcaa agtttcactg aaaactacgc 780 agggatcttc cacttccagt tctggcgcta tggagactgg gtagatgtgg ttattgacga 840 ctgtctgccg acatacaaca accagctggt cttcaccaaa tccaaccacc gcaatgagtt 900 ctggagtgct ctactggaga aagcatatgc caagctccat ggttcctatg aagctctgaa 960 aggtgggaac accacagaag ccatggagga cttcacagga ggggtgacag agttttttga 1020 gatcaaggat gctccgagtg acatgtacaa gatcatgagg aaagctatcg agagaggctc 1080 cctcatgggc tgctccattg atgatggcac caacatgact tatggaacct ctccttctgg 1140 tctgaacatg ggggaattga ttgcgcggat ggtgagaaat atggataact cgctgctcag 1200 agactcagac ctggacccca gggcctcaga tgacagaccg tcacggacaa ttgttccggt 1260 gcagtatgaa acaagaatgg cctgtggact ggtgaaaggg cacgcctatt cagtcactgg 1320 gctggaggag gccctgttca aaggcgagaa ggtgaagctg gtgcggctgc ggaacccctg 1380 gggccaggtg gagtggaacg gctcttggag tgatggttgg aaggactgga gctttgtgga 1440 caaagacgag aaggcccgtc tgcagcacca ggtcaccgag gatggagagt tctggatgtc 1500 atatgatgac tttgtctacc atttcacaaa gctggagatc tgcaacctca cagctgatgc 1560 cctggagtcc gataagcttc agacctggac agtgtctgta aatgagggcc gctgggtgag 1620 gggctgttct gctggaggct gccggaactt cccagacact ttctggacca acccgcagta 1680 ccgtctcaag ctcctggagg aggatgatga ccctgatgac tctgaggtga tttgcagctt 1740 cctcgtggct ctgatgcaga aaaatcggcg caaggaccgg aagctggggg ccaacctctt 1800 caccattggc ttcgctatct acgaggttcc caaagagatg cacgggaata agcaacacct 1860 gcagaaggac ttcttcttgt acaatgcctc caaggccagg agcaaaacct acatcaacat 1920 gcgggaggtg tcccagcgct tccgcctgcc gcccagcgag tatgtcattg tcccctccac 1980 ttacgagccc catcaggagg gggaattcat cctccgggtc ttctctgaaa agaggaatct 2040 ctctgaggaa gctgagaata caatctctgt ggaccggcca gtgaaaaaga aaaaaaacaa 2100 gcccatcatc ttcgtttcag acagagcaaa cagcaacaag gagctgggtg tggaccagga 2160 ggcagaggag ggcaaagaca aaacagggcc ggataaacaa ggggaaagcc cacagccacg 2220 gcctggccac acagaccagg agagtgagga gcagcagcaa ttccggaaca tcttcaggca 2280 gattgcaggc gacgacatgg agatctgtgc ggatgaactc aagaatgtcc ttaatacggt 2340 ggtgaacaaa cacaaggacc tgaagacaca agggttcact ctggagtcct gcagaagcat 2400 gatagctctc atggatacag atggctctgg gagactgaat cttcaagagt tccatcacct 2460 ctggaaaaag atcaaggcct ggcagaaaat cttcaaacac tatgacactg accattctgg 2520 taccatcaat agctatgaga tgcgaaatgc agtcaatgat gcaggcttcc atctcaacag 2580 ccaactctat gacatcatca ccatgcgcta cgcagacaaa cacatgaaca tcgactttga 2640 cagcttcatc tgctgcttcg tcaggctgga agggatgttc agagcttttc acgcatttga 2700 caaggatgga gatggcatca tcaaactgaa cgtacttgag tggctgcagc ttaccatgta 2760 tgcctgaacc agatgacctc atgtaagatc aaccaggatt ccatctcaac acgacacagc 2820 tagggctgtt taccacaagg aacccagtag gcacacctcc accaaactgg gctcctggtc 2880 acgttccttc tccactttga cccaagtctt ggtgcacagc cacctcaagt gtctggcttg 2940 ctgggagctc tgcagacgct gtctacatag cttgtaactg ggttgtccac agccctgtca 3000 ccatctgcac tcagttctgc cagttttagg gtgggtctac tctggggtcc atagggtgtg 3060 gatacctgac aaaaatgtgg ctacacttct gaaagaatct atctaaataa aggcacgcac 3120 atggctggtt ccaccatt 3138 

What is claimed is:
 1. A protein comprising an amino acid sequence according to SEQ ID No:.1.
 2. The protein according to claim 1 which is calpain.
 3. The protein according to claim 2 which is of the retina origin.
 4. A peptide having an amino acid sequence according to SEQ ID No:
 14. 5. A process for producing the protein according to claim 1, which comprises culturing in a culture medium a transformant transformed with a vector comprising a DNA encoding the protein according to claim 1, and producing and accumulating the protein according to claim 1 in the culture. 